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Combustion problem, Temp to high.

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Old   June 11, 2002, 14:39
Default Combustion problem, Temp to high.
  #1
Devin
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Hello everyone,

I'm trying to model an HVOF thermal spray process, but I'm having some difficulty. I'm getting temperatures in excess of 4500K when the flame temperature of propylene is approx. 2300K.

The model is using ideal-gas as it is a supersonic flow and the standard k-e model for turbulence. The boundary condition for the fuel inlet is a propylene-oxygen mixture. I suspect this may be my proplem. I've done some other cases involving separate fuel and oxygen supplies with better results.

Any thoughts?

Devin
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Old   June 12, 2002, 05:20
Default Re: Combustion problem, Temp to high.
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Erwin
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Are you using a radiation model to get rid of some energy? That might help.
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Old   June 13, 2002, 20:54
Default Re: Combustion problem, Temp to high.
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Jin-Wook LEE
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Flame temperature of propylene 'WITH AIR ' may be approx. 2300K, but flame temperature 'WITH OXYGEN' might be higher than 4500K.

Sincerely, Jinwook

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Old   June 14, 2002, 02:29
Default Re: Combustion problem, Temp to high.
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newbie
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What will the flame temperature be for kerosene and how does one go about determining the value? If I am simulating a combustor, how do i know if the flame temperature is too high?
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Old   June 16, 2002, 20:37
Default Re: Combustion problem, Temp to high.
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Jin-Wook LEE
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Adiabatic flame temperature of most fuel with 'AIR' as oxidant is about 2000C(~2300K) or higher.

Theoretically, Adiabatic flame temperature of most fuel with OXYGEN as oxidant might be higher than 4000K. But this is only theoretical value. In general they say that, in real experiment, the flame temperature is lower than 4000K because of dissociation.

Calculation of Adiabatic Flame Temperature(AFT) :

Q_in = Integral from T_ref to T_aft dot M Sigma (Cp)_i dot m_i dT

Where,

dot M : total mass flow rate dot m : mass fraction of each species Cp_i : specific heat of each species ...... ......

Sincerely, Jinwook

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Old   June 17, 2002, 15:01
Default Re: Combustion problem, Temp to high.
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Devin
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Thanks, everyone, for your input. Greatly appreciated.

Devin
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Old   April 26, 2012, 05:46
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Mohammed Khan
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Quote:
Originally Posted by Devin
;101290
Hello everyone,

I'm trying to model an HVOF thermal spray process, but I'm having some difficulty. I'm getting temperatures in excess of 4500K when the flame temperature of propylene is approx. 2300K.

The model is using ideal-gas as it is a supersonic flow and the standard k-e model for turbulence. The boundary condition for the fuel inlet is a propylene-oxygen mixture. I suspect this may be my proplem. I've done some other cases involving separate fuel and oxygen supplies with better results.

Any thoughts?

Devin
Dear Devin,
I am modeling the HVOF process in fluent and I am also getting very high temperature. I hope u got the solution for that. Could u please tell me the solution for getting the temperature around 2500.
Thanks
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